In web page, how to get the input-file-name saved on disk after user modify it in dialog-box

Question

I build a text that I want to save on my disk. I suggest a file-name, but user can modify it. How to get the final file-name ? Where can I access to this value in my following-code ? Which element contains the final file-name ?

Best regards.

/*
    */
function saveTextOnLocalFile( textToWrite , strFileName, dotAndExt) {
        
    //  create a new Blob (html5 magic) that conatins the data from your form feild
    let textFileAsBlob = new Blob([textToWrite], {type:'text/plain'});
    
    // Specify the name of the file to be saved
    if (strFileName == null) {
        strFileName = "export-" + new Date().yyyymmddhhmmss() + dotAndExt;
        }

    // create a link for our script to 'click'
    let downloadLink = document.createElement("a");
    downloadLink.download = strFileName;
    // provide text for the link. This will be hidden
    downloadLink.innerHTML = "My Hidden Link";
                
    downloadLink.href = window.URL.createObjectURL( textFileAsBlob);
    // when link is clicked call a function to remove it from the DOM in case user wants to save a second file.
    downloadLink.onclick = destroyClickedElement;       
    // make sure the link is hidden.
    downloadLink.style.display = "none";
    // add the link to the DOM
    document.body.appendChild(downloadLink);    
    // click the new link
    downloadLink.click();
    }
    
/**/
function destroyClickedElement(event) {
    let downloadLink = event.target;
    let fileName = downloadLink.download;
    // remove the link from the DOM
    document.body.removeChild( event.target);
    }